Helicopter Hover CFD Simulations: An Investigation of Various Far-Field Boundary and Initial Conditions via DLR's Legacy Block-Structured FLOWer CFD Solver

Abstract

The DLR FLOWer block-structured CFD solver which solves the Reynolds Averaged Navier-Strokes equations is employed in this paper in order to undergo an investigation of the effect of different far field boundary conditions and initial conditions of the HART II helicopter rotor in hover. A dual time stepping scheme is employed in the transient simulations to observe flow field evolution from an initial state. Parametric studies on the density residual convergence tolerance criteria and potential turbulence models are also explored to ensure an optimal compromise between accuracy and computational efficiency which were considered important due to the short period of the study and the high computational demand of hover simulations. It was concluded that a model described in recent literature tested on different domains of varying mesh densities and downstream far field boundary locations is more robust and can aid helicopter rotor hover simulations converge at a faster rate. This means that domains with shorter far field distances from the source of disturbance can be used with this new boundary condition, to decrease computational costs and therefore time.